CVE-2024-45509 is a critical access control vulnerability identified in the Malware Information Sharing Platform (MISP) up to version 2.4.196. The vulnerability resides in the app/Controller/BookmarksController.php component, which fails to enforce proper authorization checks for bookmark data access. Specifically, users who are not organization administrators can bypass access restrictions and gain unauthorized access to bookmarks data. This flaw violates the principle of least privilege, allowing attackers to read, modify, or delete bookmarks that may contain sensitive threat intelligence information. The vulnerability is remotely exploitable without requiring authentication or user interaction, as indicated by the CVSS vector (AV:N/AC:L/PR:N/UI:N). The impact spans confidentiality, integrity, and availability, making it a critical security issue. Although no public exploits have been reported yet, the high severity score (9.8) and the nature of the vulnerability make it a prime target for attackers aiming to compromise threat intelligence data or disrupt sharing operations. The underlying weakness corresponds to CWE-284 (Improper Access Control), highlighting a failure in enforcing correct permissions. Organizations using MISP should prioritize remediation once patches are available or implement strict network-level access controls to mitigate risk.

The vulnerability allows unauthorized remote attackers to access, modify, and delete bookmarks data within MISP without any authentication or privileges. This can lead to significant confidentiality breaches, exposing sensitive threat intelligence that could be used by adversaries to evade detection or plan attacks. Integrity is compromised as attackers can alter or delete critical data, undermining trust in the platform and potentially causing misinformation or loss of valuable intelligence. Availability is also at risk since attackers could delete bookmarks, disrupting normal operations and collaboration within security teams. Given MISP's role in sharing cyber threat information among organizations and governments, exploitation could have cascading effects on incident response and threat mitigation efforts globally. The ease of exploitation and lack of required user interaction increase the likelihood of attacks, potentially affecting a broad range of users and organizations relying on MISP for cybersecurity intelligence.

1. Apply patches or updates from MISP developers as soon as they become available to fix the access control flaw in BookmarksController.php. 2. Until patches are released, restrict network access to MISP instances by limiting connections to trusted IP addresses and using VPNs or secure tunnels. 3. Implement strict role-based access controls and audit user permissions regularly to ensure only authorized personnel have administrative privileges. 4. Monitor MISP logs for unusual access patterns or unauthorized attempts to access bookmark data. 5. Consider deploying web application firewalls (WAFs) with custom rules to detect and block suspicious requests targeting the bookmarks functionality. 6. Educate users and administrators about the vulnerability and encourage prompt reporting of anomalies. 7. Regularly back up MISP data, including bookmarks, to enable recovery in case of data tampering or deletion. 8. Conduct security assessments and penetration testing focused on access control mechanisms within MISP to identify and remediate similar issues proactively.